anonymous one year ago Which of the graphs below correctly solves for x in the equation x^2 − 4x + 3 = x + 3?

1. anonymous

2. anonymous

3. anonymous

i have plugged the x coordinates of the points in the x of the function and only graph that has the point (0,3) and (5,8) work and made both sides equal .. and that's answer choices A , B and , C so please help me.

4. lulubj
5. anonymous

@jim_thompson5910 @Luigi0210 @peachpi @ryamorgan284

6. anonymous

Yes , i have uploaded them in order .. first one A and B and second one is C and D

7. lulubj

Then, D

8. anonymous

How? -5 doesn't work if you plug it in the function it doesn't make both sides equal.

9. UsukiDoll

this question only concerns the x-values... $x^2-4x+3=x+3$

10. UsukiDoll

we know 0 would work because $(0)^2-4(0)+3=0+3$ $3=3$ but since there are multiple coordinates, we need to figure out if there is more than one x value that satisfies the equation

11. UsukiDoll

there's 2 intersections... for your choices... so there's more than 1 common point

12. anonymous

right, and i have done that and only the points (0,3) and (5,8) do satisfie that function

13. UsukiDoll

$(5)^2-4(5)+3=5+3$ $25-20+3=5+3$ $5+3=5+3 \rightarrow 8=8$ yeah that's correct...

14. UsukiDoll

$(-5)^2-4(-5)+3=-5+3$ $25+20+3 \neq -2$ $48 \neq -2$

15. anonymous

i think it's the second graph because if you only graph f(x) = x+3 it will only give you a linear graph that it's line only matches the second one and the last one but since the last one doesn't satisfie the function it's not correct and it's B

16. UsukiDoll

it is the second graph.. the coordinates of (0,3) and(5,8)

17. anonymous

the mistake that i have made when i tried to graph it .. i graphed it like this f(x)=x2 − 4x + 3 = x + 3 .. i should have done the left side as one graph and the second one as another graph and see the final image.

18. anonymous

Thanks a lot for your time and help. @UsukiDoll

19. UsukiDoll

oh... you have to split them up like f(x) = x+3 f(x) = x^2-4x+3 and compare the two together to see if there's a common point.

20. anonymous

aha , and that's what i did and the end

21. UsukiDoll

it helps to make a table like x f(x) = x+3 f(x) =x^2-4x+3 0 3 3 1 4 0

22. anonymous

that's how i knew B and those two points match and the others don't

23. UsukiDoll

whenever you see the same number... it's a solution to both f(x) =x+3 and f(x) = x^2-4x+3

24. anonymous

Yes.